The laptop only operates when you hold the power cord in a certain direction.
The laptop only runs on battery power.
The laptop gets no power at all.
The laptop will not charge the battery.
The laptop switches from AC power to battery power intermittently.
The laptop suddenly shuts off.
Sparks come out of the back of the laptop. (This is always bad)

Why a DC jack breaks?

The power jack on most models of laptops do not have enough reinforcement within the structure of the casing and motherboard to handle the stress caused by movement of the power plug.
Some power jacks simply fail under normal operation of your computer. After a year or two of usage, parts just come loose on certain models.
Sometimes the laptop gets dropped and the cord yanks the DC jack loose.
People, pets and vacuum cleaners trip over laptop power cords and break the power jack.
The laptop is moved around a lot. After the DC jack is moved back and forth enough times, it comes loose.

PC Workshop repair the jack on all brands of laptop computers. More accurately, we replace the DC jack in laptops. Some of the most common laptops that require DC jack repair that we see are HP (Pavilion and Omnibook ), Compaq (Armada and Presario series), Dell (Inspiron and Latitude), Acer (Travelmate and Aspire ), Toshiba (we see a lot of the Satellite series), Sony (Vaio), IBM (Thinkpad), Gateway, Emachines, Samsung, Asus and Panasonic.